This invention relates to the connection of electrical terminals to wound capacitors and, more particularly, to such connections which employ sprayed metal electrodes.
Wound capacitors typically include a pair of sheets of dielectric material, each having a conductive layer deposited on one side. The dielectric sheets are wound adjacent to each other about a common axis to provide a cylindrical assembly. An axial displacement is provided between the conductive layers so that the conductive layers are exposed at opposite ends of the cylindrical assembly. A metal electrode is formed by spraying metal on each end of the assembly, thereby short circuiting adjacent edges of the metal layer exposed at that particular end of the assembly. A conductor is then electrically and mechanically connected to the sprayed metal electrode, typically by soldering. Since some of the sprayed metals, for example, aluminum or zinc, do not solder readily, the conductor attachment must be welded or a solderable metal over-sprayed on the aluminum or zinc.
Thin dielectric capacitor films are easily damaged by heat from soldering or welding, or by flux or cleaning solutions applied prior to attachment of the conductor. Even with a highly skilled operator, there is always a danger of damaging the dielectric film during the conductor attachment process.
It is therefore desirable to provide a capacitor end terminal, which has both adequate electrical and mechanical properties, without the need for soldering or welding.